MADCAT

Links are specific items that allow items to have children coming from external database of the same workspace.
They are defined in a model by using the LINK element. When MADCAT find a LINK element in an ITEM or FOLDER element, the user will be able to create links in this ITEM or FOLDER.
In this example, the model is designed such as the user will be able to create links to renderers in the folder "Renderers" of the item "Workspace" :

Data is not duplicated in project storage but in reports and tool treatments :
You can follow a link in the explorer, this will open a new explorer with the focus on the target item :

You can also directly edit a link. You will edit the target item.

When you export the data using a report, the link is automatically replaced with its target item.

MADCAT has a function to find links pointing to a selected item. Select an item, click on the button and it runs a search which will lists all the links refering to your item :

Finally, when you perform an action on a link, the tool will "see" the target item but not the link like reports. It can directly read or edit the attributes of the target item.